Andy Serkis creates a conversation between Caesar the ape and Gollum

Andy Serkis, best known for making CGI characters come to life, brought two of them into the same conversation on Thursday night’s Conan.

The actor — on the show promoting Dawn of the Planet of the Apes, out July 11, in which he reprises his role of ape-leader Caesar — demonstrates some gorilla-speak to host Conan O’Brien and Andy Richter, which inspires O’Brien to ask, “What would it be like if (Lord of the Rings‘) Gollum wanted to have a conversation with Caesar … if he called him on the phone?”